Israel and Syria agreed today to resume peace negotiations that broke off nearly four years ago, raising hopes for an end to half a century of conflict, including the continuing low-grade war in southern Lebanon.

The agreement between Israel and one of its most implacable Arab enemies is a major foreign policy victory for President Clinton, who made the announcement in Washington following a flurry of phone calls to Israeli Prime Minister Ehud Barak and Syrian President Hafez Assad. The breakthrough apparently occurred Tuesday at a meeting in Damascus between Assad and Secretary of State Madeleine K. Albright.

Speaking at a news conference at the State Department, Clinton announced that Barak and Syrian Foreign Minister Farouk Charaa would meet in Washington next week for one or two days of talks, which he said would then continue in the region. Clinton said he had taken a "blood oath" to refrain from discussing details of the renewed talks, but called them "a significant breakthrough."

The agreement signals a concession by Syria, which has long insisted that Israel make a commitment to returning the Golan Heights--captured by Israel in 1967--as a condition for resuming talks. A senior U.S. official who briefed reporters in Jerusalem said the two sides had agreed to resume the talks with "no preconditions" following months of private diplomatic exchanges on issues ranging from security arrangements to water rights.

"Israelis and Syrians still need to make courageous decisions in order to reach a just and lasting peace," Clinton said. "But today's step is a significant breakthrough, for it will allow them to deal with each other face to face, and that is the only way to get there. . . . Before us is a task as clear as it is challenging. As I told Prime Minister Barak and President Assad in phone conversations with them earlier today, they now bear a heavy responsibility of bringing peace to the Israeli and Syrian people."

White House aides said it is possible that Assad, who is in poor health, may meet directly with Barak when the talks move to a Middle East site to be determined after the initial round in Washington. They said Clinton and Barak had spoken today with Palestinian leader Yasser Arafat to reassure him that the Israeli-Syrian talks will not diminish the importance of ongoing peace negotiations between Israelis and Palestinians.

Those talks--aimed at reaching the broad outlines of a final peace settlement by mid-February--stalled earlier this week after Palestinian negotiators insisted that Israel put a stop to construction activity in the West Bank. But Albright appeared to have at least partly defused that controversy, telling reporters after a meeting with Arafat tonight in the West Bank City of Ramallah that the Palestinians had agreed to continue the talks without interruption.

Until the last day or two, the Palestinian track of the peace process had largely eclipsed the Syrian one as U.S. and Israeli officials grew skeptical about whether Assad was serious about wanting to return to the negotiating table. But in some respects it is more urgent for Israel, whose forces are bogged down in a war of attrition with Syrian-backed Hezbollah guerrillas in southern Lebanon. Israel occupies the area as a buffer against attacks on northern Israel.

Syria, which keeps 35,000 troops in Lebanon, permits Hezbollah to operate as a means of maintaining pressure on the Jewish state. Israeli officials say they will not sign any peace settlement with Damascus that does not include security guarantees for its northern border.

After months of stalemate, Israel formally suspended talks with Syria following a wave of terrorist bombings by Palestinian militants in early 1996. Israel said the climate was no longer conducive to further negotiations.

But hopes for a settlement soared earlier this year as Assad and Barak exchanged mutual expressions of praise following Barak's election in May. At the same time, the autocratic Syrian leader has insisted that Israel live up to what he says was a commitment made by then-Prime Minister Yitzhak Rabin to withdraw from the Golan Heights to the line Israel held on June 4, 1967, at the outbreak of the Six Day War.

Israel, with U.S. backing, has maintained that Rabin's proposal--relayed through then-Secretary of State Warren G. Christopher shortly before Rabin's assassination in 1995--was a purely "hypothetical" one aimed at judging Syria's willingness to meet Israel's demands for full peace and normal relations.

But after a series of contacts with U.S. officials, including a meeting between Clinton and Charaa in late September, Syria has apparently backed away from its demand that Israel commit to such a withdrawal as a condition of resuming talks.

In a formulation that apparently is designed to give diplomatic cover to the hard-line Arab leader, Clinton said the two sides have agreed to resume the negotiations "from the point where they left off"--phrasing that each side is free to interpret as it pleases.

An Israeli cabinet minister said tonight that the formula allowed each side to stick to its position on where they broke off four years ago.

"We said we were prepared to continue negotiations at the point where they stopped and that each side will come with its own view on where the negotiations were stopped," the minister, Haim Ramon, told Israel Radio. "This is exactly what happened. Nothing has been promised to Syria."

A Syrian Presidential Palace statement said Assad welcomed the announcement by Clinton. During their phone call, it said, the two men "expressed their determination to exert all possible efforts to achieve a comprehensive and just peace in the region."

Asked what helped trigger the breakthrough, White House national security adviser Samuel R. "Sandy" Berger said, "There's no question that Barak's election provided both Arafat and Assad with an interlocutor who was deeply committed to the peace process and who had a strong constituency to move it forward. In the beginning there were some nice noises that Barak and Assad made to each other. . . . It's taken several months to sweep away the obstacles to get this done."

U.S. officials said their discussions with Syria have centered not only on how far Israel would withdraw from the Golan but also on the "character" of the peace, as well as diplomatic relations and timing. These discussions, they said, have given Syria and Israel a clear understanding of the other's needs that could make it possible to move fairly quickly to a settlement--although they cautioned that the two sides remain far apart on a number of key issues.

Barak, after a morning meeting with Albright, concurred with the American view. "I think that basically we know all that we can know about his [Assad's] positions, and he knows all that he can know about about our positions, short of making the decision," Barak said at a news conference with Albright.

Before Clinton's announcement, a buoyant Albright telephoned three Arab leaders--Egyptian President Hosni Mubarak, Jordan's King Abdullah and Crown Prince Abdullah of Saudi Arabia--to inform them about the resumption of talks. She made the calls from Ramallah, where she met this evening with Arafat.

Amid signs that Barak may be edging closer to negotiations with Syria there were also signs of unease from Jewish settlers in the Golan._

About 17,000 Israelis live in the Golan, and many of them are bitterly opposed to handing back the territory in return for a comprehensive peace deal with Damascus. A group representing the residents of the Golan was seeking a meeting with Barak, and insisting that Israelis are generally opposed to a complete pullback from the Heights. However, some polls have suggested that many Israelis accept the idea of giving the Golan back to Syria, provided Israel's security can be assured through a variety of measures, possibly including international monitoring.

Staff writer Charles Babington in Washington contributed to this report.